Innovative, lots of room to move around, employees are treated well in terms of salary and benefits. Amazing people who can make your job fun and energizing.

Cons

Politics stifles innovation. Dissent is still politically loaded, and depending on your group, career suicide. Culture of silence around bad managers means there are many bad ones, more than you'd expect, at a large, productive company. Some of the folks who've been around a long time, and are very senior in the company, need to be moved around, or out.

The internship program at Microsoft is excellent. They seem to treat interns as full time employees in terms of work. They also have lots of pretty fun events over the course of the summer and you get a chance to meet a lot of other interns and network within the company. They also pay really well.

Cons

The project I was given could have been more interesting, but that seems to vary a lot between interns.